I am planning to build a counterflow wort chiller using a hose outside of a copper tube. There are a great variety of lengths and types available commercially and I have read that many commercial solutions are not long enough to chill properly

What is the optimal length for a counter flow wort chiller? It seems that with counterflow, it should not matter whether you are chilling 3 or 5 gallons. Is this correct? Do you just need the correct length to ensure that wort entering at ~200 deg F cools to <=70 deg F by the end?

Are there any particular construction materials and/or designs that work particularly well? I am planning to purchase hose rated to up to 212 deg F, copper tubing, and T (or similar) fitting on each side to separate hose from tubing.

2 Answers
2

The wort should be flowing through the copper tubing in this case, so heat shouldn't be an issue. Copper is also great because it transfers heat well.

If you have a control over the flow rate of the wort, then the length isn't really that important. Realize that the longer the length of copper, the faster you'll be able to run the wort through and cool it properly. My counterflow chiller is probably about 10' of tubing, though I'm not sure of the exact length.

In terms of tubing to run the water through, most people just use ordinary garden hose - I don't know that it's rated at 212, but with water flowing, it'll never reach anything like 212. Copper has a melting point well into the thousands, so no worries about cooper and heat. Just make sure that if you solder any connections, you use a lead free solder.

The cooling rate is going to depend on how cold your cold water is and the flowrates of the hot wort and the cooling water. From my experience, I've had a hard time finding food-grade hose that can handle boiling liquid and still seal reliably against a plain copper hose. If you can get a barb fitting, you'll have an easier time.

EDIT: I should clarify--the hose that you use for the outer portion shouldn't matter. As long as you have a reasonable flowrate for your cooling water, you shouldn't have to worry. You will, however, likely want some sort of heat-resistant hose for getting the wort from your brewkettle into your wort chiller. I've been using polyethylene, because it's the only food-grade hose I can find locally that can handle the heat, but it does a miserable job sealing against the fittings.

Good call on the poly tube and barb fitting.
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Mike SNov 10 '10 at 18:49

part of the problem, I think, is that polyethylene is somewhat self-lubricating under stress, now, if I can just find a way to get a barb on the plain, somewhat tapered ends of my wort chiller... Also, I'd love to find an auto-siphon or pump that can handle the hot liquid, since I cant siphon with a leaky hose.
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TristanNov 10 '10 at 20:18